Climate and monthly weather forecast
Grinnell, IA

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Weather in January

January, like December, is a freezing cold winter month in Grinnell, Iowa, with an average temperature varying between 13.8°F (-10.1°C) and 27°F (-2.8°C). Grinnell's coldest weather arrives in January, when temperatures average a high of 27°F (-2.8°C) and a low of 13.8°F (-10.1°C). Weather in January »

Weather in February

The last month of the winter, February, is another freezing cold month in Grinnell, Iowa, with an average temperature ranging between min 17.4°F (-8.1°C) and max 31.1°F (-0.5°C). The onset of February brings an average high-temperature of a still freezing cold 31.1°F (-0.5°C), nearly matching the January temperature. Weather in February »

Weather in March

The first month of the spring, March, is a frosty month in Grinnell, Iowa, with an average temperature varying between 45.7°F (7.6°C) and 31.3°F (-0.4°C). As February transitions into March, a clear upsurge in temperatures is observed, with average highs advancing from a freezing cold 31.1°F (-0.5°C) to a frosty 45.7°F (7.6°C). Weather in March »

Weather in April

April in Grinnell, Iowa, is a mild spring month, with an average temperature varying between 41.9°F (5.5°C) and 58.5°F (14.7°C). As April begins, there is an increase in the average high-temperature, moving from a frosty 45.7°F (7.6°C) in March to a refreshing 58.5°F (14.7°C). Weather in April »

Weather in May

The last month of the spring, May, is a pleasant month in Grinnell, Iowa, with an average temperature ranging between min 52.3°F (11.3°C) and max 69.3°F (20.7°C). As May arrives, Grinnell's weather shows an increase in high-temperatures, moving from April's refreshing 58.5°F (14.7°C) to an agreeable 69.3°F (20.7°C). Weather in May »

Weather in June

The first month of the summer, June, is a warm month in Grinnell, Iowa, with temperature in the range of an average low of 62.4°F (16.9°C) and an average high of 78.4°F (25.8°C). The start of June is characterized by an increase in the average high-temperature, transitioning from a pleasant 69.3°F (20.7°C) in May to a moderately hot 78.4°F (25.8°C). Weather in June »

Weather in July

July, the same as June, is another warm summer month in Grinnell, Iowa, with an average temperature varying between 64.8°F (18.2°C) and 81.1°F (27.3°C). In Grinnell, the month of July registers the highest temperatures, averaging 81.1°F (27.3°C) at the peak and 64.8°F (18.2°C) at the lowest. The heat index value for July is estimated at a tropical 87.8°F (31°C). Weather in July »

Weather in August

August, the last month of the summer in Grinnell, is another warm month, with an average temperature varying between 80.2°F (26.8°C) and 62.2°F (16.8°C). Welcoming August, Grinnell notes an average high-temperature of a still warm 80.2°F (26.8°C), nearly consistent with July's 81.1°F (27.3°C). Weather in August »

Weather in September

The first month of the autumn, September, is still a warm month in Grinnell, Iowa, with an average temperature fluctuating between 74.7°F (23.7°C) and 55.8°F (13.2°C). During the shift to September, a minor reduction in average high-temperature is observed, shifting from 80.2°F (26.8°C) in August to a still moderately hot 74.7°F (23.7°C). Weather in September »

Weather in October

October, like September, is a moderate autumn month in Grinnell, Iowa, with an average temperature varying between 44.4°F (6.9°C) and 59.9°F (15.5°C). With the transition into October, Grinnell experiences a significant decrease in average high-temperatures, moving down from a moderately hot 74.7°F (23.7°C) in September to a mild 59.9°F (15.5°C). Weather in October »

Weather in November

November, the last month of the autumn in Grinnell, is another chilly month, with an average temperature varying between 32.5°F (0.3°C) and 46.2°F (7.9°C). Onset of November witnesses a reduction in the average high-temperature, falling from a moderate 59.9°F (15.5°C) in October to a chilly 46.2°F (7.9°C). Weather in November »

Weather in December

The first month of the winter, December, is also an icy month in Grinnell, Iowa, with an average temperature fluctuating between 33.1°F (0.6°C) and 22.1°F (-5.5°C). December shows a mild decline in the average high-temperature, falling from November's frosty 46.2°F (7.9°C) to a wintry 33.1°F (0.6°C). Weather in December »
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Frequently asked questions

What are the coldest months in Grinnell?

The coldest period in Grinnell is January, when temperatures fluctuate between an average high of 27°F (-2.8°C) and a low of 13.8°F (-10.1°C).

What is the most humid month in Grinnell?

January is the most humid month, with an average relative humidity of 84%.

What is the driest month in Grinnell?

The month with the least rainfall is January, when the rain falls for 4.3 days and typically collects 0.47" (12mm) of precipitation.

How many days does it rain in Grinnell?

In Grinnell, during the entire year, the rain falls for 117.5 days and collects up to 13.03" (331mm) of precipitation.

When does it snow in Grinnell?

January through May, October through December are months with snowfall in Grinnell.

When does it snow the most in Grinnell?

January is the month with the most snowfall in Grinnell. Snow falls for 8.1 days and accumulates 1.81" (46mm) of snow.

How many days does it snow in Grinnell?

Throughout the year, in Grinnell, Iowa, there are 30.7 snowfall days, and 6.06" (154mm) of snow is accumulated.

What is the month with the least sunshine in Grinnell?

With an average of 4.1h of sunshine, January has the least sunshine of the year in Grinnell.

What is the month with the lowest UV index in Grinnell?

January is the month with the lowest UV index, with an average maximum UV index of 1.

When is Daylight Saving Time (DST) in Grinnell?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Grinnell, Iowa, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.

What is the wettest month in Grinnell?

The months with the most rainfall in Grinnell are May and June, with an average 1.97" (50mm) of precipitation.

When it does not snow in Grinnell?

In Grinnell, Iowa, snow does not fall in June through September.

When are the longest days in Grinnell?

The month with the longest days in Grinnell is June, with an average of 15h and 12min of daylight.

When is the highest UV index in Grinnell?

The months with the highest UV index are June and July, with an average maximum UV index of 6.

What are the warmest months in Grinnell?

July stands out as Grinnell's warmest month, with an average high-temperature of 81.1°F (27.3°C) and a low-temperature of 64.8°F (18.2°C).

What month has the most sunshine in Grinnell?

The month with the most sunshine is July, with an average of 10.2h of sunshine.

What is the least humid month in Grinnell?

With an average relative humidity of 71%, October is the least humid month in Grinnell, Iowa.

What is the month with the shortest days in Grinnell?

With an average of 9h and 12min of daylight, December has the shortest days of the year in Grinnell, Iowa.

Average temperature
Grinnell, IA

Average temperature - Grinnell, IA

The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (27°F).

The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (13.8°F).

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Average pressure
Grinnell, IA

Average pressure - Grinnell, IA

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).

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Average wind speed
Grinnell, IA

Average wind speed - Grinnell, IA

The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest month (with the lowest average wind speed) is August (7mph).

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Average rainfall
Grinnell, IA

Average rainfall - Grinnell, IA

The wettest months (with the highest rainfall) are May and June (1.97").
The driest month (with the least rainfall) is January (0.47").

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Average rainfall days
Grinnell, IA

Average rainfall days - Grinnell, IA

The month with the highest number of rainy days is June (15.1 days).
The month with the least rainy days is February (4.1 days).

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Average snowfall
Grinnell, IA

Average snowfall - Grinnell, IA

The month with the highest snowfall is January (1.81").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days
Grinnell, IA

Average snowfall days - Grinnell, IA

The month with the highest number of snowfall days is January (8.1 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight / Average sunshine
Grinnell, IA

Average daylight / Average sunshine - Grinnell, IA

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).

The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).

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Average sunshine days
Grinnell, IA

Average sunshine days - Grinnell, IA

The month with the most sunshine days is January (21.1 days).
The month with the least sunshine days is June (11.5 days).

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Average visibility
Grinnell, IA

Average visibility - Grinnell, IA

The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).

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Grinnell, Iowa, USA

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